Impact fuze for projectiles

ABSTRACT

An impact fuze for projectiles of the type containing a controllably adjustable escapement regulator for determining the post-bore safety period, i.e. the safe period of the fuze after leaving the barrel. Means are provided for adjusting the running time of the escapement by altering the depth of engagement between the escapement wheel and the escapement lever. These means may comprise a bearing pin having portions of different diameters which is displaceable so that the different diameters can be selectively engaged by the bearing bore of the escape lever to vary the depth of the engagement. The bearing pin may form the striker pin of the fuze. Thus it is possible for the post-bore safety period of the projectile to be adjusted by a gun crew before the firing of the gun to defend gun positions against a surprise attack launched from nearby.

I United States Patent 1 1 1 1 3,715,989 Apotheloz [451 Feb. 13, 1973 1 IMPACT FUZE FOR PROJECTILES Twin Prima ExaminerSamuel W. En 1e l w g [75] lnvemor' gsgf g alhsenen AttorneyWenderoth, Lind & Ponack [73] Assignee: Werkzeugmaschinent'abrilt O erlikon [57] ABSTRACT Buhrle AG, Zurich, Switzerland An impact fuze for projectiles of the type containing a controllably adjustable escapement regulator for [22] F'ledi 1971 determining the post-bore safety period, i.e. the safe [2]] Appl 137,213 period of the fuze after leaving the barrel. Means are provided for adjusting the running time of the escapement by altering the depth of engagement between the [30] Appllcatlon Pnonty escapement wheel and the escapement lever. These May 1, 1970 Switzerland ..6593/70 means may comprise a bearing P having Portions of different diameters which is displaceable so that the 52 us. or. ..102/s4, 58/116, 74/1.5 different diameters eeh he Seleetively engaged by the 51 Int. Cl. ..F42c 9/04 hearing here of the eseape lever to y the depth of [58] Field of Search ..102/s4; 58/116, 117-, 74/15 the engagement The bearing P may ferm the Striker pin of the fuze. Thus it is possible for the post-bore [56] References Cited safety period of the projectile to be adjusted by a gun crew before the firing of the gun to defend gun posi- UNITED STATES PATENTS tions against a surprise attack launched from nearby. 3,168,833 2/1965 Popovitch ..102/84 X F8210 ..74/l.5 2 Claims 2 Drawing Figures 2:126:047 8/1938 ....102 s4 1,266,687 5/1918 .lunghans ..l02/84 PATENTEDFEB13 1915 3,715,989

SHEET 10F 2 Fig.!

ROBERT APOTHELOZ,

Inventor Attornuys SHEET 2 OF 2 PATENT'EUFEB 13 ms ROBERT APOIHELOZ,

IMPACT FUZE FOR PROJECTILES The invention relates to an impact fuze for projectiles of the type containing a controllably adjustable escapement regulator for determining the post-bore safety period, i.e., the safe period of the fuze after leaving the barrel.

In a known fuze of this type the escapement regulator contains an escape wheel and an escape lever, the latter being mounted in a bush fitted into a plate and embracing the striker pin. The time it takes the carrier of the detonator pellet to turn from the safe into the armed position, which time determines the post-bore safety period of the fuze, is fixed by the construction of the escapement regulator and by the characteristics of the spring driving the pellet carrier. This time cannot be adjusted by the gun crew. If the fuzes of artillery projectiles have a lengthy post-bore safety period, the guns cannot be used to defend the gun positions against a surprise attack launched from near by.

It is an object of the present invention to eliminate this drawback and to provide a fuze in which the postbore safety period can be adjusted before the firing of the gun.

The invention provides an impact fuze for projectiles of the type containing a controllably adjustable escapement regulator said fuze comprising an escapement wheel and an escapement lever for determining the safe period of the fuze after leaving a barrel, in which for adjusting the running time of the escapement the depth of engagement between the escapement wheel and the excapement lever is adjustable.

In a particular embodiment of the invention the impact fuze contains means for displacing a bearing pin so that portions of the pin having different diameters engage the bearing bore of the escape lever and thereby vary said depth of engagement.

An embodiment of the invention will be more particularly described with reference to the drawings in which:

FIG. 1 is a longitudinal section of a fuze according to the invention, and

FIG. 2 is a section taken on the line II-II in FIG. 1.

Referring to FIG. 1 a body 1 is mounted in a central blind bore 3 of a frustroconical main body 2 of a fuze. A sleeve 4 having a transverse extension 5 is also mounted in the bore 3 with its rear annular face 6 bearing on the body 1. A fuze head 7 having a central bore 8 is rotatably supported in the front end portion of the bore 3. Two pins 9 extend transversely to the fuze axis, so as to face each other along a common diameter. The pins 9 pass through the body 2 of the fuze and engage in slots 10 in the head 7. A central portion 12 of the slots 10 is helical, whereas the longitudinal axis of end portions 11 of the slots are normal to the fuze axis. A sleeve 13 is slidably movable in the bore 8 of the head 7. A spring 14 supported by the extension 5 of the sleeve 4 bears against the base 15 of the sleeve 13. The sleeve 13 has a shoulder 16 which is urged by the spring 14 into contact with an annular rim 17 of the bore 8 of the fuze head.

A bearing pin 18 which functions as a striker pin is attached to the base 15 of the sleeve 13. The pin 18 extends into a bore 19 in the extension 5 of the sleeve 4 and passes through a chamber 20 defined between the sleeve 4 and the body 1 into a bore 21 in the body 1. An escape lever 22 of an escapement regulator is located in the chamber 20. The lever 22 contains a bore 23 through which the bearing pin 18 passes. The diameter of a portion 24 of the bearing pin 18 is equal to that of the bore 23 in the escape lever. The bearing pin 18 also 5 includes a portion 25 of reduced diameter. Truncated conical surfaces 26 are formed at the ends of the portions 25.

The escape lever 22 is provided with studs 27 having crown shaped heads 28 that contact the front surface of the body 1. The escape lever 22 has two pallet faces 29, 30 (FIG. 2). A detonator pellet carrier 31 in the form of a rotor is contained inside a bore 32 in the body 1 and is rotatable about a shaft 33 mounted in the body 1. A bore 34 in the rotor 31 is coaxial to the bore 21 in the body 1 when the rotor 31 is in its safe position. The rotor 31 has a gear 35 which in a manner not shown meshes with a pinion 36 (FIG. 2). The pinion 36 is operatively connected by a gear train comprising the gear wheels 37, 38, 39, 40 in the chamber 20 to a further pinion 41. The latter pinion 41 is coupled to an escape wheel 42 which has teeth 43 and is mounted on a shaft 44 supported in the body 1. A coiled torsion spring 45 is attached to the rotor 31. The escape lever 22 is prevented from moving towards the front of the fuze by the interposition of the wheels 39, 40 which cover the lever.

The manner in which the described fuze functions is as follows:

With reference to FIG. 1 the fuze has been set for a predetermined post-bore safety period. The pins 9 engage the rear ends 11 of the slots 10 in the fuze head 7. The bearing pin 18 is in a position in which the bore 23 of the escape lever 22 is on a level with the pin portion 24 having the larger diameter.

When the projectile fitted with the fuze is fired, the sleeve 13 and the bearing pin 18, which also forms the striker pin, will be thrown rearwards by inertial forces against the resistance of the spring 14. The bearing pin 18 is thereby pushed to the rear through the bore 23 in the escape lever 22 and its point 46 enters a bore 34 in the rotor 31. When the projectile has left the muzzle of the barrel of the gun and the accelerating forces cease, the sleeve 13, urged by the spring 14, slides forward again until intercepted by the rim 17 in the fuze head 7. The point 46 of the bearing pin 18 is thereby retracted from the bore 34 in the rotor, and portion 24 of the pin reenters the bore 23 of the escape lever.

After its release the rotor 31 begins to be driven by the torque of the spring 45 and this causes the pinion 36 to rotate. The rotary motion of the pinion 36 is transmitted by the transmission train 37, 38, 39, 40, 41 to the escape wheel 42 which (in FIG. 2) will rotate anticlockwise.

However, the cooperation of the escape lever 22 with the escape wheel 42 reduces the speed of rotation of the rotor 31.

For setting the fuze to a shorter post-bore safety period the head 7 is turned, causing the pins 9 to slide along the helical portions 12 of the slots 10 into the front end portions 11 of the slots. This rotation causes the fuze head 7 to be displaced to the rear, the sleeve 13 and hence the bearing pin 18 being displaced in the same direction. The portion 25 of the bearing pin 18 having the smaller diameter thus enters the bore in the escape lever 23. After its release the escape lever 22 is forced away from the escape wheel 42 by the thrust exerted by the teeth 43 of the wheel on the pallet faces 29, and that side of the bore 23 which faces away from the wheel will therefore make contact with the reduced section 25 of the bearing pin. The distance between the fulcrum of the escape lever and the center of the escape wheel is thereby slightly increased and the depth of engagement of the escape wheel 42 with the escape lever 22 is now less than when the lever 22 works on the section 24 of the bearing pin 18. This change in the geometrical relationships reduces the amplitude of oscillation of the escape lever 22 and hence raises the running speed of the escapement regulator 22, 42. The time needed for the fuze to be armed is therefore reduced and the safety period after leaving the barrel is shorter.

In fuz'es intended for spin-stabilized projectiles the movement of the escape lever 22 away from the escape wheel 42 can be assisted by offsetting its center of gravity from the axis of rotation. The centrifugal forces which then act on the escape lever 22 when the projectile spins will throw the lever away from the escape wheel 42 against the portion 25 of the bearing pin and retain the lever at this greater radial distance.

The disadvantages achieved by the invention reside more particularly in that by merely turning the head of the fuze the safety period of projectiles after leaving the barrel can be adjusted to desired values so that the same projectile can be used for firing at distant and at close targets.

I claim:

1. An impact fuze for rotating projectiles of the type containing a controllably adjustable escapement regulator comprising an escapement wheel; an escapement lever having its center of gravity offset from the axis of rotation, said escapement lever being engageable with said escapement wheel; a bearing pin axially shiftable in relation to said escapement lever, said escapement lever being pivotally mounted on said bearing pin, said bearing pin having a first section with a first diameter and a second section with a second diameter smaller than said first diameter; whereby in a first position of said bearing pin said escapement lever pivots around said first section of said bearing pin and in a second position of said bearing pin said escapement lever pivots around said second section of said bearing pin; and whereby under the centrifugal forces acting during rotation of said projectile on said escapement lever in said second position of said bearing pin the escapement depth between said escapement wheel and said escapement lever is smaller than in said first position of said bearing pin, said escapement depth being determinative of the running time of said regulator; and means to axially shift said bearing pin from said first position into said second position to change said running time.

2. An impact fuze for projectiles of the type contain ing a controllably adjustable escapement regulator comprising an escapement wheel; and escapement lever engageable with said escapement wheel; a bearing pin axially shiftable in relation to said escapement lever, said escapement lever being pivotally mounted on said bearing pin, saidbearing pin having a first section with a first diameter and a second section with a second diameter smaller than said first diameter;

whereby in a first position of said bearin pin said escapement lever pivots around said first sec 10" of said bearing pin and in a second position of said bearing pin said escapement lever pivots around said second section of said bearing pin; and whereby under the forces actuated by said escapement wheel on said escapement lever in said second position of said bearing pin the escapement depth between said escapement wheel and said escapement lever is smaller than in said first position of said bearing pin said escapement depth being determinative-of the running time of said regulator; and means to axially shift said bearing pin from said first position into said second position to change said running time. 

1. An impact fuze for rotating projectiles of the type containing a controllably adjustable escapement regulator comprising an escapement wheel; an escapement lever having its center of gravity offset from the axis of rotation, said escapement lever being engageable with said escapement wheel; a bearing pin axially shiftable in relation to said escapement lever, said escapement lever being pivotally mounted on said bearing pin, said bearing pin having a first section with a first diameter and a second section with a second diameter smaller than said first diameter; whereby in a first position of said bearing pin said escapement lever pivots around said first section of said bearing pin and in a second position of said bearing pin said escapement lever pivots around said second section of said bearing pin; and whereby under the centrifugal forces acting during rotation of said projectile on said escapement lever in said second position of said bearing pin the escapement depth between said escapement wheel and said escapement lever is smaller than in said first position of said bearing pin, said escapement depth being determinative of the running time of said regulator; and means to axially shift said bearing pin from said first position into said second position to change said running time.
 1. An impact fuze for rotating projectiles of the type containing a controllably adjustable escapement regulator comprising an escapement wheel; an escapement lever having its center of gravity offset from the axis of rotation, said escapement lever being engageable with said escapement wheel; a bearing pin axially shiftable in relation to said escapement lever, said escapement lever being pivotally mounted on said bearing pin, said bearing pin having a first section with a first diameter and a second section with a second diameter smaller than said first diameter; whereby in a first position of said bearing pin said escapement lever pivots around said first section of said bearing pin and in a second position of said bearing pin said escapement lever pivots around said second section of said bearing pin; and whereby under the centrifugal forces acting during rotation of said projectile on said escapement lever in said second position of said bearing pin the escapement depth between said escapement wheel and said escapement lever is smaller than in said first position of said bearing pin, said escapement depth being determinative of the running time of said regulator; and means to axially shift said bearing pin from said first position into said second position to change said running time. 